It is often desirable to know the angular position of a rotating member (e.g., a shaft). Such sensing is used in connection with a variety of rotary devices such as, for example, motors and actuators such that exact angular position thereof is determinable. As one example, in an application where an actuator controls a gaseous valve throttle opening or fuel pump rack position, angular position feedback is desirable such that a precise amount of admitted air or fuel is determinable. Further, an angular position feedback sensor is generally used to enhance the positionability of the actuator it is affixed to using conventional closed-loop servo control techniques.
Several different technologies exist for angular position sensors. One particular technology used in many aggressive environments is magnetic sensing technology. Magnetic sensors are generally contactless and frictionless, and thus feature high reliability, long-life, and dirt and dust immunity.
Unfortunately, magnetic sensor technology suffers from linearity problems. These are due to the choice and configuration of magnetic circuit elements within the angular position sensor. A sensor having good linearity over a wide range of rotation has been long sought after.
The present invention is directed toward a solution to the above-identified problem.